反应详情

To a stirred solution of 3-(benzyloxycarbonylamino)-3-methylbutanoic acid (11.8 g, 46.8 mmol) in DMF (100 mL) was added CDI (7.60 g, 1 equiv, 46.8 mmol) in one portion and stirred at room temperature for 2 h. Piperidine (9.27 mL, 2 equiv, 93.6 mmol) was added and the reaction was left to stir for 17 h. The solvent was removed on a rotovap and the residue was dissolved into a mixture of ethyl acetate (300 mL) and water (100 mL). The organic layer was separated and washed with saturated NaHCO3 solution (2×150 mL), 1 N HCl solution (150 mL) and brine (150 mL). It was dried over anhydrous MgSO4, filtered and concentrated to an oil. The crude material was purified on an ISCO system using a 220 g column and ethyl acetate and hexanes as eluent. The desired fractions were collected and concentrated to a colorless oil (8.84 g, 60%). 1H NMR (CDCl3, 400 MHz): δ 1.45 (s, 6H), 1.48-1.57 (m, 4H), 1.60-1.66 (m, 2H), 3.40-3.44 (m, 2H), 3.52-3.58 (m, 2H), 5.04 (s, 2H), 6.15 (s, 1H), 7.27-7.37 (m, 5H). LRMS (ESI+) for C18H26N2O3 (318.2); Found: 319 (MH+).

1. waitthe reaction was left
2. stirringto stir for 17 h
3. customThe solvent was removed on a rotovap
4. dissolutionthe residue was dissolved into a mixture of ethyl acetate (300 mL) and water (100 mL)
5. customThe organic layer was separated
6. washwashed with saturated NaHCO3 solution (2×150 mL), 1 N HCl solution (150 mL) and brine (150 mL)
7. dry with materialIt was dried over anhydrous MgSO4
8. filtrationfiltered
9. concentrationconcentrated to an oil
10. customThe crude material was purified on an ISCO system
11. customThe desired fractions were collected
12. concentrationconcentrated to a colorless oil (8.84 g, 60%)